Yup, unfortunately, a lot of web WYSIWIG editors use Java, which isn't supported on iPad.
I use SquareSpace for my website, WoowooMac.com, and I have the same problem.
However, I am able to copy text from the SqureSpace editor. Then, I use GoodReader or Gusto to edit. I paste the edited text back into the field. Not great, but at least I have a way to edit on my iPad if I really need to.